Outdoor umbrellas have been in use for many years but they must be opened and closed manually. When an umbrella is left open and the weather changes abruptly, often there is no time to close the umbrella or the owner is not available to do so. If there are high winds the umbrella canopy can sustain damage or the entire umbrella can be lifted from its anchor and travel some distance, causing damage to anything on which it may land. Additionally, the umbrella canopy and support system can be severely damaged when the umbrella falls.
There have been umbrellas developed to prevent wind damage when the umbrella is left open. Culver, in U.S. Pat. No. 6,330,886, discloses an outdoor umbrella with a canopy composed of a plurality of wedge shaped metal vanes or panels. The vanes are arranged such that one edge of each vane overlaps the next adjacent vane. A portion of each vane may lift free of the adjacent vane in a wind, thus the canopy is vented and does not rise in the wind. This umbrella can be closed manually.
In U.S. Pat. No. 4,319,600, Roche teaches an outdoor umbrella assembly designed to prevent the umbrella from lifting off its mounting when subjected to gusts of wind. The canopy of the umbrella is supported by a series of braces connected to' a slidable hub located on the main support post. Within the main support post is a movable auxiliary post surrounded by a spring. The auxiliary post is guided to move vertically only. The spring causes the auxiliary post to resist but not prevent upward movement of the auxiliary post relative to the main post when wind acts on the canopy. When the wind lifts the canopy, the spring allows the hub to move downwardly. When the wind stops the hub moves upwardly to its former position. A control rod limits the downward movement of the hub. Thus the canopy essentially flaps up and down in the wind. The canopy can be manually closed with a crank and cable assembly.
Various forms of self-closing umbrellas have been reported. In U.S. Pat. No. 2,183,833 to Farhar teaches a coin operated umbrella that is permanently installed on a beach. A coin starts an electric motor that activates a chain driven pinion gear which raises a rack and the attached umbrella from its cylindrical housing. There is a timer in cooperation with the motor so that when the specified time has elapsed the motor reverses and the umbrella is drawn back into the housing. Electricity is supplied through underground cables.
An outdoor umbrella that can close completely by itself when subjected to strong winds is taught by Houston in U.S. Pat. No. 3,680,571. The umbrella is supported by a hollow support post in two telescoping sections. The upper section moves within the lower section. There is a helical spring mounted within the upper section which urges it upward when the umbrella is folded. The canopy is supported by a series of ribs pivotally connected at their upper ends to the upper section. The lower ends of the ribs are connected to a sleeve that is slidably mounted for limited movement on the lower section. When a high velocity wind lifts the canopy the ribs bow upwardly causing the sleeve to move upwardly as does the upper section until the canopy closes. Suitably positioned detent members are released allowing the spring to expand and the umbrella to close. The umbrella can be opened and closed manually with a conventional crank and cable. The mechanism of this invention relies on the lifting effect of a strong wind on the canopy to actuate the closing mechanism. If there is wind, but not strong enough, the fabric of the canopy can be damaged and the umbrella will not close.
There is a need for a self closing umbrella that does not depend upon the effect of the wind to lift the canopy of the umbrella. There is a need for a self closing umbrella that is sensitive to wind, that closes quickly and that remains closed until manually reopened. There is a need for an umbrella having a self-closing mechanism that is automatically reset when the umbrella closes.